The present invention relates, in general, to telecommunications and, more particularly, to a system and methods for detecting an interfering signal in voice communication.
In acoustic communications, interfering signals degrade the acoustic signal transmission. For example, in telephony applications an acoustic signal may be transmitted by a far-end device and received by a near-end device, where the near-end device outputs the signal through, for example, a speaker. Some of this signal may be picked up by a near-end microphone and transmitted to the far end. If the level of the loudspeaker signal is sufficiently high, the far-end talker would hear an echo, which is annoying. Techniques for removing this echo have been described in U.S. Patent Application Publication No. 2012/0307980 A1 by Arvindh Krishnaswany, titled “Audio Quality and Double Talk Preservation in Echo Control for Voice Communications,” published on Dec. 6, 2012. An interfering signal that complicates the removal of echo signals is double-talk. Double-talk occurs when the individuals at the near-end and the far-end side of an acoustic communications system speak simultaneously. Detecting double-talk has been difficult and has been discussed in U.S. Patent Application Publication No. 2008/0101622 A1 by Akihiko Sugiyama, titled “Signal Processing Method, Signal Processing Device, and Signal Processing Program,” and published on May 1, 2008, U.S. Pat. No. 8,041,028, titled “Double-Talk Detection,” issued to Kathryn Adeney on Oct. 18, 2011, and U.S. Pat. No. 8,064,966, titled “Method of Detecting Double Talk Situation for a ‘Hands-Free Device,” issued to Michael Herve et al. on Nov. 22, 2011.
Accordingly, it would be advantageous to have a structure and method for detecting double-talk. It would be of further advantage for the structure and method to be cost and time efficient to implement.
For simplicity and clarity of illustration, elements in the figures are not necessarily to scale, and the same reference characters in different figures denote the same elements. Additionally, descriptions and details of well-known steps and elements are omitted for simplicity of the description. It will be appreciated by those skilled in the art that the words during, while, and when as used herein are not exact terms that mean an action takes place instantly upon an initiating action but that there may be some small but reasonable delay, such as a propagation delay, between the reaction that is initiated by the initial action and the initial action. The use of the words approximately, about, or substantially means that a value of an element has a parameter that is expected to be very close to a stated value or position. However, as is well known in the art there are always minor variances that prevent the values or positions from being exactly as stated.